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#21
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Will the investment flood happen?
"Joann Evans" wrote:
Richard Schumacher wrote: A vertical-takeoff vertical-landing rocket ought to be less susceptible to weather than any airplane, true? It doesn't rely on aerodynamic lift (except perhaps very early in the re-entry, when it will be miles above the weather anyway), so there's none of that nonsense about crosswinds or icing. As we've seen with Apollo 12, there could be issues with cloud electrical potentials, though. If the exhaust trail enhances conductivity to ground, it's a path almost directly there, as opposed to an HTO that may ascend into the clouds at a shallower angle. Understand, I think VTVL is the way to go in most cases (espically at very large payloads) but this has to be considered. I don't believe that Apollo / Saturn V was specifically designed to withstand lightning strikes. At least not at an operational level. Most modern aircraft are, and many aircraft are struck by lightning in flight without causing severe (or any) problems for the fligt. I see little reason why rockets couldn't be made equally robust. |
#22
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Will the investment flood happen?
In article ,
Richard Schumacher wrote: if it's pouring down rain and shows no signs of stopping -- bearing in mind that in Northern Europe, one major terminus for intercontinental runs, this is far from rare :-) -- you have to be able to fly through it. A vertical-takeoff vertical-landing rocket ought to be less susceptible to weather than any airplane, true? In principle, yes. Helicopter landing approaches have far lower weather minima than fixed-wing landings. Much depends on details, though. -- MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer first ground-station pass 1651, all nominal! | |
#23
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Will the investment flood happen?
"John Ordover" wrote:
Uh - Fedex routinely delivers overnight, and has same-day service already (on the sender's end, you have to drop it off at the airport, because the flight time isn't the problem, it's the ground-time and sorting. If you go to the airport yourself and put it in the right bin yourself, no problem getting it across the US the same day). A flight from CA to NYC -already- takes only a few hours, usually around 5, plus or minus a little depending on weather, which way you're going, etc. Paying a higher price to cut the five hours to 2.5, say, or even 2, cutting the delivery time from a same-day ten hours to a same-day 8 hours, isn't likely to be worth it to anyone often enough to make the advance in technology worth it. When FedEx means "sameday" they mean just barely so, since the flight alone takes several hours. Also, you're missing an important aspect of the differing situations, yet again. Next day / sameday is a step up in cost and speed from ground. It also entails a step up in handling, both on the ground and by the customers. Taking another step up in cost and speed to fast package sub- orbital delivery would also warrant an equivalent step up in ground operations. Specifically, at that cost level individual courier services for *each* package would be a no brainer, as the cost would be less than the shipping. Similarly, expedited processing would be a sure thing as well. The point is, there's no barrier, assuming sub-orbital rocketplanes are available for the task, to providing delivery service across the continental US in only a few hours (not just barely within the same day some of the time, but within the *work day* most of the time, and actually within the same day all of the time). But that's only the tip of the iceberg, because sub- orbital fast package delivery could deliver anywhere in the world within the same day, every day. That's an even more profound jump in capabilities. Though it would require expedited customs procedures. If there are billions of dollars at stake because a factory is missing a part, it's a simple matter to hire a high-speed private jet to get you what you need. Heck, with that much money at stake, you can -buy- a private jet. This supports your argument how? If even a 1 hour speedup is worth nearly any price they'd pay, then they'd certainly spring for rocket service if they could get it, even if it only shaved off the slightest amount of time. If a company can pay millions of dollars to deliver one package then they can damned well afford a sub-orbital rocket trip at any conceivable operating price given today's technology. That is, in the end, the problem with the Concorde as well. There simply weren't enough people who wanted to pay between 10 and 20 times the fare just to cut three hours off a six hour flight. That's not half of the problem with Concorde. More importantly, you're comparing apples and oranges. Concorde flies maybe 2 or 3 times faster than regular commercial jets. Whether you fly the Concorde or a regular jet it still takes hours to cross the atlantic and it still takes a good day or so for a trip there or the trip back. With the Concorde you end up with a bit more time left over for your day, and if you really push it you can just barely go across the Atlantic and back in one day, but really it's not much different or terribly faster than a normal jet. A sub-orbital rocketplane would fly up to 12 times faster than the Concorde, and that's a quantitative difference large enough to make a qualitative difference. With a sub-orbital vehicle, a trans-continental trip would take as much time as an ordinary commute. It would only take a small amount of a day, and would leave you with plenty of time for other activities. A one day round trip would actually leave enough time during the day to be worthwhile, a weekend trip even more so. There just might be enough people to buy trips or delivery services at that level of speed and convenience. |
#24
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Will the investment flood happen?
"Christopher M. Jones" wrote:
"Joann Evans" wrote: Richard Schumacher wrote: A vertical-takeoff vertical-landing rocket ought to be less susceptible to weather than any airplane, true? It doesn't rely on aerodynamic lift (except perhaps very early in the re-entry, when it will be miles above the weather anyway), so there's none of that nonsense about crosswinds or icing. As we've seen with Apollo 12, there could be issues with cloud electrical potentials, though. If the exhaust trail enhances conductivity to ground, it's a path almost directly there, as opposed to an HTO that may ascend into the clouds at a shallower angle. Understand, I think VTVL is the way to go in most cases (espically at very large payloads) but this has to be considered. I don't believe that Apollo / Saturn V was specifically designed to withstand lightning strikes. At least not at an operational level. Most modern aircraft are, and many aircraft are struck by lightning in flight without causing severe (or any) problems for the fligt. I see little reason why rockets couldn't be made equally robust. Fortunately, the the Apollo-Saturn stack happened to be sufficently robust on that occasion, and there may be room for improvement. But the point is, aircarft generally don't ascend almost vertically, leaving a potentially conductive trail on the shortest path back to ground. Under those circumstances, you may *cause* a discharge that otherwise might not have happened. It's been done deliberately (rockets trailing wires) for research purposes, many times. Further complicating the matter (and this is already a consideration for newer aircraft) is the fact that a VTO commercial launcher is likely to use assorted composites in its construction (including low-temprature potrions of its outer surfaces) for weight savings, rather than conductive metals that could pass the energy around the interior.... |
#25
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Will the investment flood happen?
In article ,
Keith F. Lynch wrote: That's a somewhat silly concern; we launch almost all our spacecraft out of somewhere much less than a half hour's flight time for the rocket out from DC. Who is "we"? The government itself? What does that prove? We're discussing privately owned and operated rockets. Almost all rockets launched from (e.g.) the Cape are privately owned and operated nowadays. -- MOST launched 1015 EDT 30 June, separated 1046, | Henry Spencer first ground-station pass 1651, all nominal! | |
#26
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Will the investment flood happen?
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#27
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Will the investment flood happen?
When FedEx means "sameday" they mean just barely so, since the
flight alone takes several hours. Not at all. You can drop a package at LAX and pick it up in NYC about five hours later. That's hardly "barely" same day - if you did it at 9 LA time, the package would be in NYC five hours later, at 2 LA time or 11 NY time. Either way, that's good, solid, same-day. Cut the flight time to 2.5 hours, you're really not making much of an improvement, and for this you would need to develop and deploy a whole new system, at the cost of billions? Also, you're missing an important aspect of the differing situations, yet again. Next day / sameday is a step up in cost and speed from ground. It also entails a step up in handling, both on the ground and by the customers. Taking another step up in cost and speed to fast package sub- orbital delivery would also warrant an equivalent step up in ground operations. Specifically, at that cost level individual courier services for *each* package would be a no brainer, as the cost would be less than the shipping. Similarly, expedited processing would be a sure thing as well. But if you only step up the ground operations, which is easier said than done and also very expensive because the way to do it is to increase the number of employees who work on each package, you'd cut the delivery time down substantially without having to deploy new technolgooy. The extreme example is hiring one person per package, and having them deliver only that one package each day. That would cut your delivery time by at least 50%, but is too expensive - except on those rare occassions when something has to be somewhere at high speed - in which case you -do- hire one person per package to bring the missing part, or whatever, to its destination. So a 50% delivery speed increase involves no new technology, no new flying system. I mean, just from my own personal experience fed-exing rush blues to the printer, I drove to the airport (30 mins) and handed it to the fed-ex operation there. It was at its desintation in Canada 2 hours later, where someone from the printer picked it up and took 30 mins to drive to their office, where they called me to tell me they got it. It was expensive and time consuming for us, but it got done. The point is, there's no barrier, assuming sub-orbital rocketplanes are available for the task, to providing delivery service across the continental US in only a few hours (not just barely within the same day some of the time, but within the *work day* most of the time, and actually within the same day all of the time). There is no technological barrier. There is a huge economic barrier. Like I said, same-day service is only a matter of having a person take the item from door to door personally. I could easily grab a package, hop on a 7:am flight from LGA to LAX, arrive 3pm LA time and be at my LA destination by 3 LA time. So why develop rocket planes for a same-day service that is so rarely needed, and that already exists? But that's only the tip of the iceberg, because sub- orbital fast package delivery could deliver anywhere in the world within the same day, every day. That's an even more profound jump in capabilities. Though it would require expedited customs procedures. There isn't enough of a market to drive the development. If there are billions of dollars at stake because a factory is missing a part, it's a simple matter to hire a high-speed private jet to get you what you need. Heck, with that much money at stake, you can -buy- a private jet. If even a 1 hour speedup is worth nearly any price they'd pay Please list for me about 10,000 instances of this happening every day, because that's about how many ou'd need to make it pay. There just might be enough people to buy trips or delivery services at that level of speed and convenience. There isn't. |
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